,substrate and ground plane, reducing the contact voltage about 2 V in the simulations. Fig. 3 shows the displacement as a function of the beam height. This displacement is independent of the beam height when fringing effects are neglected. However, when beam height decreases, the fringing capacitance increases resulting in an increase of the force and displacement for a given applied voltage. This result demonstrates again that to take into consideration fringing fields is essential in these structures. Finally, Fig. 4 shows the simulated force at the contact with and without the inclusion of fringing effects. This figure shows that fringing effects increase the capacitance and the force. This fact improves the contact reducing its resistance and the switch losses. The measured performance of the manufactured device is shown in Fig. 5, along with its photograph [5]. Insertion loss is 0.13/0.41 dB at 0.9/6 GHz, return loss is 37.7/28.7 dB at 0.9/6 GHz and isolation is 60.2/31 dB at 0.9/6 GHz. These results are comparable to the ones obtained in [4] on a highresistivity silicon substrate. 4. CONCLUSIONS A model for prediction of the actuator displacement in electrostatically actuated, lateral contact RF MEMS series switches has been presented, a switch topology with increasing acceptance due to the evolution of thick metal layers technology. It has been demonstrated that in this topology the parallel-plate approximation for actuator displacement can not be assumed. In addition, it has also been demonstrated the importance of considering fringing fields in the model for a reliable prediction. The simulated results match very well with the measured actuation characteristics of a series switch with electrostatic interdigital actuation manufactured with MetalMumps TM .
[1]
C.S. Park,et al.
An intelligent power amplifier MMIC using a new adaptive bias control circuit for W-CDMA applications
,
2004,
IEEE Journal of Solid-State Circuits.
[2]
William H. Press,et al.
Numerical Recipes in C, 2nd Edition
,
1992
.
[3]
Ali Hajimiri,et al.
Fully integrated CMOS power amplifier design using the distributed active-transformer architecture
,
2002,
IEEE J. Solid State Circuits.
[4]
D. McCormick,et al.
A low-voltage lateral MEMS switch with high RF performance
,
2004,
Journal of Microelectromechanical Systems.
[5]
Yun-Seong Eo,et al.
A fully integrated 24-dBm CMOS power amplifier for 802.11a WLAN applications
,
2004
.
[6]
Gabriel M. Rebeiz,et al.
High-isolation CPW MEMS shunt switches. 1. Modeling
,
2000
.
[7]
P. Blondy,et al.
A DC to 100 GHz high performance ohmic shunt switch
,
2004,
2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535).
[8]
Ai Qun Liu,et al.
Low-loss lateral micromachined switches for high frequency applications
,
2005
.
[9]
H. Nishiyama,et al.
Capacitance of a strip capacitor
,
1990
.
[10]
A. Giry,et al.
A 1.9 GHz low voltage CMOS power amplifier for medium power RF applications
,
2000,
2000 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium Digest of Papers (Cat. No.00CH37096).
[11]
H. Saunders,et al.
Finite element procedures in engineering analysis
,
1982
.